The Stovebolt Site Forums The Shop Area Driveline 57 3 Speed Tranny to 1946 1/2T

Hi All,

I know the answer is on here but my searches are coming up empty. I have been told by other SB members that there "may" be an adaptor available to make it possible to install a 1957 pickup engine and 3 speed transmission into a 1946 1/2T as I am told the drive shaft is different. Can anyone point me in the right direction please. I have a 1946 1/2T with a tired 216 that I am replacing with a 235 with a 3 speed transmission. I have other threads on the forums but the motor and tranny I am acquiring has changed so I thought a new thread would be best.

Many thanks!

Patrick

Are you sure you want to stop using the 46 transmission?
Using the 57 transmission will require changing the rear end to an open drive style.
You can use your 46 transmission with the 235.

Hi Dave,

Thanks for your response.

Your answer is what I was looking for, though not what I was hoping to hear. I could have sworn there was a "adaptor" to allow the newer transmission to bolt up to the enclosed drive shaft. Alas, such is not my luck. LOL :-) The existing transmission is a 4 speed non-syncro (crashbox?) which is fine. I grew up on a farm so I am familiar with how to shift it without TOO much grinding. I was just hoping to be able to use the 3 speed that is coming with the 235 motor without having to jump through Too many hoops. The 4 speed does not allow the pedal assembly to mate up to the current bell housing on the 216 motor 100% and I will need to make some type of bracket to secure it to the bell housing as suggested by another SB member. Currently the pedal assembly is only secured by the pedal shafts into the transmission... the bolt holes connecting the pedal assembly to the bell housing do not line up.

Patrick

The easiest way to go would be to use a 1938-47 truck bellhousing and if you want to go 3 speed, a 1940-47 truck 3 speed.

This will all mate to the 235 and the inclosed torque tube. No adapters needed.

The clutch and brake bracket will also bolt up to this setup, although you will need to place shims between the mount and transmission, as the 3 speed is slightly narrower than the 4 speed.

Good morning Dave,

I pulled the trigger on the 235. I can't use the transmission anyways as it is a column shift. Unless I can find a 3 speed locally (per your suggestion), I plan on using the 4 speed that's already in the truck.

Thanks for your help!

Patrick

Pre '68 Dave. I have a 1946 granny low 4 speed, If I wanted to would it fit on my 1954-3100? It was from a Federal Forestry service truck. If not it may help Patrick M. Doc

A 1946 4 speed has a different bolt pattern than 1948 and later, and it is shorter than the SM420 that started in 1948.

Hi Doc, Thanks. Much appreciated. I currently have a 4 speed installed. Maybe you can both take a look at the attached picture. The foot pedal assembly bolt pattern does not line up with the bell housing # 839257. I am guessing either the transmission or bell housing are not correct or normal for the truck which is a 1/2T? It has been suggested to me to make a bracket to connect the 2 which I am ok with, but if there is a better way such as replacing the bell housing, etc... I am all ears.

Dave, I am also going to need to order the water pump conversion plate at some point if you are still supplying them.

The reason the bolts do not line up with the bellhousing is because you have a 3 speed mount on a wider 4 speed transmission. It is easy to cut back the mounting points on the bracket to move it over so the bellhousing bolt holes line up. That way the pedals will come through the floor in the correct position also.
That is essentially what the factory did when a 4 speed was used. If in the future you go back to a 3 speed you will need to put shims between the mount and transmission.

I do have plenty of water pump adapters.

Patrick,
You need the proper (earlier) bellhousing as indicated by Pre '68 Dave. Your pedal assembly, as pictured, is not properly attached and I would hate to see you attempt a panic stop and break something!
Kent

That is the correct bellhousing.
The next generation bellhousing does not have provisions for the mount.

After seeing Pre '68 Dave's post at the bottom of page 1, I believe he is correct. There is a different part number for the pedal and master cylinder mount listed for 3 spd and 4 spd transmissions (group # 4.648). So Patrick just needs to find the proper mount or modify the one he has. No need for a different bellhousing. Thanks for the correction, Dave.

Kent

Pre '68 Dave, thank you for the info for me and Patrick M. I was going to talk to my mechanic ( and friend), about a conversion but I'm sure he will tell me your correct. Ed

👍

Any thoughts on finding a bracket that is already setup for the 4-speed transmission? Would you guys agree the correct part number is 477083 based on the snip from the parts catalog attached?

477083 looks correct!

Thank you Dave.

Thanks so much for the great information. I have been holding on to the 1946 1/2 ton granny low 4 speed for about 20 years,thinking I may use it in case my 54-3100 needed it. Now I know. Do you think there is a market for it? Doc

Thanks so much for the great information. I have been holding on to the 1946 1/2 ton granny low 4 speed for about 20 years,thinking I may use it in case my 54-3100 needed it. Now I know. Do you think there is a market for it? I have the tailpiece and speedometer gear. Doc